Effects of Hydrogen Addition to SI Engine on Knock Behavior

Graphical Abstract AbstractExhaust gas fuel reforming has been identified as a thermochemical energy recovery technology with potential to improve gasoline engine efficiency, and thereby reduce CO2 in addition to other gaseous and particulate matter (PM) emissions. The principle relies on achieving energy recovery from the hot exhaust stream by endothermic catalytic reforming of gasoline and a fraction of the engine exhaust gas. The hydrogen-rich reformate has higher enthalpy than the gasoline fed to the reformer and is recirculated to the intake manifold, i.e. reformed exhaust gas recirculation (REGR).The REGR system was simulated by supplying hydrogen and carbon monoxide (CO) into a conventional EGR system. The hydrogen and CO concentrations in the REGR stream were selected to be achievable in practice at typical gasoline exhaust temperatures. Emphasis was placed on comparing REGR to the baseline gasoline engine, and also to conventional EGR. The results demonstrate the potential of REGR to simultaneously increase thermal efficiency, reduce gaseous emissions and decrease PM formation.

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“…This agrees with previous research that has shown EGR dilution [15,32,33] and hydrogen enhancement [8,34] to be effective for attenuating knock.…”

Section: Estimated Exhaust Stream Hydrogen Concentration H2ex (Ppm)supporting

confidence: 82%

Improving gasoline direct injection (GDI) engine efficiency and emissions with hydrogen from exhaust gas fuel reforming

Fennell

Herreros

Tsolakis

2014

International Journal of Hydrogen Energy

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“…If the burning velocity is increased and the combustion period is shortened, the occurrence of knock may be suppressed. Hydrogen, when added to gasoline, has been found to increase the burning velocity and therefore control the onset of knock; this might also be due the obstruction of radical production by hydrogen [8]. However it is the occurrence of pre-ignition that leads to backfire that has raised some important obstacles to the growth of hydrogen engines.…”

Section: Introductionmentioning

confidence: 99%

“…However, automotive manufacturers are seriously challenged today not only by legislative demands of low emissions but also by the need to decrease their dependency on non-renewable fuels, therefore, hydrogen has recently been the subject of much discussion, research and publications. In the past few years, research on hydrogen engines has been reported by several engine manufacturers [3][4][5][6][7][8], with BMW leading the way [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen SI and HCCI Combustion in a Direct-Injection Optical Engine

Rosati¹,

Aleiferis²

2009

SAE Int. J. Engines

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The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under the supervision of the session organizer. This process requires a minimum of three (3) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. ISSN 0148-7191 Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. SAE ABSTRACTHydrogen has been largely proposed as a possible alternative fuel for internal combustion engines. Its wide flammability range allows higher engine efficiency with leaner operation than conventional fuels, for both reduced toxic emissions and no CO 2 gases. Independently, Homogenous Charge Compression Ignition (HCCI) also allows higher thermal efficiency and lower fuel consumption with reduced NO X emissions when compared to Spark-Ignition (SI) engine operation. For HCCI combustion, a mixture of air and fuel is supplied to the cylinder and autoignition occurs from compression; engine is operated throttle-less and load is controlled by the quality of the mixture, avoiding the large fluid-dynamic losses in the intake manifold of SI engines. HCCI can be induced and controlled by varying the mixture temperature, either by Exhaust Gas Recirculation (EGR) or intake air pre-heating. A combination of HCCI combustion with hydrogen fuelling has great potential for virtually zero CO 2 and NO X emissions. Nevertheless, combustion on such a fast burning fuel with wide flammability limits and high octane number implies many disadvantages, such as control of backfiring and speed of autoignition and there is almost no literature on the subject, particularly in optical engines. Experiments were conducted in a singlecylinder research engine equipped with both Port Fuel Injection (PFI) and Direct Injection (DI) systems running at 1000 RPM. Optical access to in-cylinder phenomena was enabled through an extended piston and optical crown. Combustion images were acquired by a highspeed camera at 1° or 2° crank angle resolution for a series of engine cycles. Spark-ignition tests were initially carried out to benchmark the operation of the engine with hydrogen against gasoline. DI of hydrogen after intake valve closure was found to be preferable in order to overcome problems related to backfiring and air displacement from hydrogen's low density. HCCI combustion of hydrogen was initially enabled by means of a pilot port injection of n-heptane preceding the main direct injection of hydrogen, along with intake air preheating. Sole hydrogen fuelling HCCI was finally achieved and made sustainable, even at the low compression ratio of the optical engine by means of closed-valve DI, in synergy with air-pre-heating and negative valve overlap to promote intern...

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“…The effect of hydrogen addition on knock behavior is reported by Shinagawa et al [6]. They found that hydrogen addition can reduce the margin between ignition timing which causes knock and that for minimum spark advance for best torque (MBT).…”

Section: Introductionmentioning

confidence: 85%

Experimental investigation of the effect of spark plug gap on a hydrogen fueled SI engine

Çeper

2012

International Journal of Hydrogen Energy

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Effects of Hydrogen Addition to SI Engine on Knock Behavior

Cited by 30 publications

References 9 publications

Improving gasoline direct injection (GDI) engine efficiency and emissions with hydrogen from exhaust gas fuel reforming

Improving gasoline direct injection (GDI) engine efficiency and emissions with hydrogen from exhaust gas fuel reforming

Hydrogen SI and HCCI Combustion in a Direct-Injection Optical Engine

Experimental investigation of the effect of spark plug gap on a hydrogen fueled SI engine

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